Finish the Google login

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The description richly discloses behavior beyond the annotations: it saves tokens to an owner-only file, verifies via a read-only identity call, handles partial permission grants by still saving the login and reporting missingScopes, replaces previous logins with best-effort refresh token revocation, and returns previousAccountEmail. This goes well beyond the basic annotation hints.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is dense but efficient: four sentences cover purpose, postcondition, partial-permission handling, and account-replacement behavior. Every sentence adds meaningful information, and the key purpose is front-loaded in the first sentence.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a zero-parameter tool with no output schema, the description is complete: it explains what happens, what is returned, what happens on partial permission, and what happens when switching accounts. No important invocation or result information is missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The tool has zero parameters, so the input schema already covers everything. The description adds value by explaining what the response contains and the side effects of invoking the tool, which is useful context even though no parameter documentation is needed.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool finishes the second step of Google login, saves tokens to an owner-only file, verifies the login via a read-only identity call, and returns account email and granted scopes. This distinguishes it from the sibling start_login by explicitly labeling it as the second step and describing its specific outcome.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description gives clear context: this is the second step after browser consent, and after success every tool works immediately without restart. It also clarifies behavior under partial permission grants and account replacement, but it does not explicitly name alternatives or state when not to use it, so it falls short of full when/when-not guidance.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.